One that hurts poor people more than wealthy - since wages are last to inflate. Additionally, wealthy people are still able to afford necessities during times of high inflation.
Only if the wealth is held as dollars or a depreciating asset. If it’s invested or converted to something of limited supply then it can be inflation proof. Too bad those options are out of reach for the poor.
We have wealth taxes. They are called property taxes and inheritance taxes.
Inheritance tax is easy to avoid and property is a very small proportion of the ultra-rich's assets.